Red Warnings for Heavy Rain issued in Northland, Auckland north of Orewa, and the Coromandel Peninsula, New Zealand

Another atmospheric river event is forecast to bring more heavy rain across parts of New Zealand’s North Island in the coming days following an unprecedented rainfall event that brought severe flooding to the Auckland area and left 4 people dead on January 27, 2023.

• Heavy rain with the potential for thunderstorms and downpours returns to northern areas early on Tuesday and will continue into Wednesday
• Auckland has now recorded over 769% of its average January rainfall and over 38% of its entire annual rainfall
• The city is currently challenging the record for its wettest month ever. With more rain today and tomorrow, this formidable record may also be toppled

Localized parts of Northland (especially north of Whangārei) could see in excess of 200 mm (7.9 inches) of rainfall in around 24 hours which, given the already sodden ground, could bring about flooding quickly. Parts of Auckland could see a further 100 mm (3.9 inches) or more and people should be preparing for further rain-related impacts from late on Tuesday into Wednesday, January 31 into February 1.

After consultation with the local regional councils MetService has issued Red Warnings for Heavy Rain in Northland, Auckland north of Orewa, and the Coromandel Peninsula.

The Red Warnings have been triggered because of the likely impacts – significant flooding, slips, and further damage to roads and power networks. Previous heavy rainfall since Friday means that these regions are already saturated, still cleaning up from the last event, and are vulnerable to further heavy rain.

On Tuesday, January 31, there is the added risk of Thunderstorms for Northland, which could bring downpours. This thunderstorm risk spreads over northern Auckland from Tuesday evening and then further south into Coromandel on Wednesday, February 1.

“In consultation with Regional Councils and Civil Defence, MetService has elevated the warnings that have already been in place for these areas to Red Warnings – MetService’s highest regional warning color. This is because of the forecast intensity of the rainfall in regions that are already saturated,” said MetService meteorologist Lewis Ferris.

“People in areas under Orange Warnings for Heavy Rain also need to remain vigilant, as significant impacts are still possible in these regions, especially if the soil is saturated or infrastructure is affected already,” Lewis added.

Red Warnings are reserved for the most impactful weather events and it’s likely there will be further flooding, slips, power outages, and disruptions to travel so MetService urges people to keep up to date with our forecasts and follow the advice of local authorities.

The weather station located at Auckland Airport has an unbroken record of weather observation since 1962 and prior to Friday, the wettest ever day there amounted to 161.8 mm (6.37 inches) of rain.

On Friday, January 27, that same site reported 245 mm (9.65 inches) of rain, surpassing the previous record by over 50%.

Other weather stations around the region also reported remarkable rainfall, with many spots noting between 250 – 300 mm (9.84 – 11.81 inches) of rain within the day.

Some stations even reported over 80 mm (3.15 inches) of rain in an hour.

To put this into context, the highest classification for intense rain at MetService is ‘torrential’, which is defined as 40 mm (1.57 inches) of rain or more in an hour.

The heavy rain has led to widespread, severe flooding in the region, leaving 4 people dead.

Extreme and unprecedented: Severe flooding hits Auckland after entire summer’s worth of rain in a single day, New Zealand

References:

¹ Upper North Island not out of the woods yet – MetService – January 30, 2023

² Concerns for further impactful weather prompts MetService Red Warnings – MetService – January 30, 2023

³ Extreme and unprecedented: Severe flooding hits Auckland after entire summer’s worth of rain in a single day, New Zealand – The Watchers – January 28, 2023

Featured image credit: NIWA Weather